Multi-gap collimation lens for use in direct-view storage tube



R. D. KETCHPEL. 2,950,408

Filed oct. 50, 1959 MULTI-GAP COLLIMATION LENS FOR USE IN DIRECT-VIEW STORAGE TUBE Aug. 23, 1960 United States PatentY C i MULTI-GAP COLLIMATION LENS FOR USE 1N DIRECT-VIEW STORAGE TUBE Richard D. Ketchpel, Los Angeles, Calif., assignor to Hughes Aircraft Company, Culver City, Calif., a corporation of Delaware Filed Oct. 30, 1959, Ser. No. 849,796

3 Claims. (Cl. 313-82) This invention relates to an improved multi-gap collimation lens especially adapted for use in a direct-view storage tube and more particularly to the manner in which electrical connections are made to the successive conductive annular ring-shaped electrodes of the multigap collimation lens.

In the operation of a direct-view storage tube it is necessary to direct a beam of ood electrons uniformly over the entire area of a storage screen. To accomplish this function in `an optimum manner, it is desirable to employ several annular electrodes disposed concentrically about the inner periphery of the tube envelope. P- tentiials are applied to the annular electrodes to lirst expand the electrons as they leave the ood gun and then to collimate the flow of these electrons in a direction normal to the storage screen. In applying these potentials to the annular electrodes, a diculty arises because they are disposed on the inner surface of the tube envelope and no leads, even though insulated, can be allowed to run through the central portion of any of the electrodes. On the other hand, it becomes increasingly awkward to make external connections directly through the tube envelope to the respective annular electrodes, particularly with regard to locating the external leads and mounting the tube.

lt is therefore an object of the present invention to provide an improved apparatus for making electrical oonnections to a series of annular electrodes disposed concentrically about the inner surface of a tube envelope.

Another object of the present invention is to provide appropriate connections to a plurality of annular electrodes disposed concentrically labout the inner surface of a tube envelope, said connections being grouped so as to be adaptable for use with a plug.

Still another object of the invention is to provide respective electrical connections to each of a plurality of annular elect-redes disposed about the inner surface of a tube envelope without locating any leads Within the center portions of the electrodes and fwithout exposing the leads on the exterior of the tube.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent by reference to the following description taken in conjunction with the accompanying drawings, wherein:

Figure l shows a cross-sectional schematic representation of a direct-view storage tube incorporating the improved electrical lead-in apparatus of the present invention; and

Fig. 2 illustrates a plan view of the electrical lead-in apparatus of Fig. l.

Referring now to Figure l, there is illustrated a di- 4rect-view storage tube which incorporates electrical connections made in accordance with the present invention. The direct-view storage tube comprises an evacuated envelope which includes a funnel portion 11, a face plate 12 `at the right extremity thereof, as shown in the drawing, and an axially aligned neck portion 13 at the 4and coextensive with the viewing screen 18 on the inside of the envelope 10 there is a storage screen 19 and a collector grid 20. At the left extremity of the funnel portion 11 of the evacuated envelope 10, as viewed in the drawing, there is disposed a flood gun 22 which is disposed concentrically about the longitudinal axis of neck portion 13 and has a central aperture of suiiicient diameter to lallow the electron beam produced by gun 15 to pass therethrough while it is scanned over the storage screen 19. The iiood `gun 22 produces a broad beam of electrons which are uniformly distributed and collimated over the entire area of the storage screen 19.

Apparatus for uniformly distributing and collimating the iiow of ood electrons comprises a multi-gap collimation lens 24 which comprises conductive electrodes 25, 26, 27, which are disposed about the inner surface of the evacuated envelope 1G in succession from the electron gun 15 to the collector Igrid 20. A plan view of the manner in which electrical contact is made to the conductive electrodes 25, 26, 27 is illustrated in Figure 2. Refem'ng to both Figures l and 2 of the drawings, a stem 3i) including conductive pins 31, 32, 33, is sealed in the wall portion of evacuated envelope 10. Prior to placing the conductive coating constituting the electrodes 25, 26, 27 on the glass envelope, a conductive strip 34 of silver paint, for example, is sprayed on the glass from the pin 31 to a region defined by dashed lines 35 which region will lie beneath the conductive electrode 25. Similarly, conductive strips 36, 38 are sprayed on the inner surface of evacuated envelope 10 from the pins 32, 33, respectively, to regions dened by dashed lines 37, 39, which regions will lie beneath the conductive electrodes 26, 27. After the three strips 34, 36, 38 have been painted or sprayed on the inner surface of the .glass envelope 10, the envelope is baked out at a temperature of 450 C.

Next, the regions defined by dashed lines 35, 37, 39 are masked and the portion of the stern 30 on the inside of the envelope 10 and the remaining portions of the conductive strips 34, 36, 38 are painted with a glass frit mixture. This glass frit mixture may, for example, be composed of 186 PK glass frit and collodion. The tube is then baked out again at 450 C. which converts the -frit mixture into a vglazed layer 40 which insulates all but the portions of the strips 34, 36, 38 which lie, respectively, in the regions defined by dashed lines 35, 37, 39 from the inner regions of the tube envelope 10. rl'hus, when the conductive electrodes 25, 26, 27 are disposed and painted about the inner surface of the tube envelope 10 they make electrical contact respectively with the strips 35, 37 and 39. These conductive coatings 25, 26, 27 may be provided, for example, by a colloidal solution of graphite in water known commercially as aquadag External electrical connections to the pins 31-33 may `be simplified by the use of a plug 42 which has receptacles that are preferably keyed so that it may be iitted over the pins 31-33 in a particular manner, thereby to greatly simplify the application of predetermined electrical voltages to the conductive coatings 25, 26, 27.

What is claimed is:

l. In =a device of the type employing a plurality of annular electrodes disposed concentrically about the inner surface of a glass envelope, the improvement comprising a stem having a corresponding plurality of conductive 3 v L pins therethrough sealed in the w'all of said glass en velope, a strip'of conductive material extending' lat-ed relationship from each of said conductive pins to -a Apoint on the inner surface of said glass envelope be- Y 'neath the respective annular electrode, and-aV layer 'of 'in- Ysulative material disposedV intermediate said strips of conductive materiali-and said annular'electrodes extending from each of said conductive pins to a point along l the respective strip of conductive material that is beneath vthe corresponding annular electrode whereby each of said conductive pins is electrically connected to a selected one of said annular electrodes.

2. In a direct-view storage tube of the type including an evacuated `envelope which houses a storage screen having 5a' charge pattern produced thereon to control Vlthe ow of a .beamY of ood electrons from a ood gun to a view lingscrreen thereby tor render lsaid charge pattern visible,

the improvement comprising: as an apparatus for univ VV afTlie'invention according vto claim the wall of said envelope; a trstconductive strip disposed directly on the inner surface of said envelopeY from Vsaid rst pin to a point beneathvsaid first annular electrode; a second conductive strip disposed directly on the inner surface of said envelope from said second pin and beneath said first annular, electrode to a point beneath said second annular electrode; and a layer of insulative ma.- terialr, disposed intermediate said second conductive strip and said iirst annular electrode :whereby said iirst and secondipins are electrically connected, respectively, to said iirst |and second annular electrodes; Y Y Y 2 wherein said iirst and second conductive strips are constituted of silver paint, said layer of insulative material is provided by a fuzed layer of glass trit,` and said first and second annular electrodes are constituted of layers of graphite.

References Cited in the'le of this patent UNITED VsTAjr/Es v,Plaintiffs 2,160,799 Teal'...i v May 30, 1939 -V 2,184,922 Gunzel Dec. 26, 1939 2,219,107 Langmuir Y.. Oct. 22, 1940 second conductive pins disposed therethrough sealed in e Y 2,562,163 Y Hiensch July '31, 1951 

